This invention relates in general to rotating part seals and in particular to a new and useful liquid packing for shafts.
Shaft packings are employed for sealing the gap between the rotating shaft and the housing of fluid-power machines for compressing and expanding gases. The great heat produced by the friction between the rotating and the non-rotating seal ring due to the needed contact pressure therebetween must be dissipated, in a manner known per se, by unilaterally cooling the seal rings with packing fluid. To a small extent, some of the packing fluid leaking under excess pressure through the gap between the seal rings and the gas space and mainly lubricating the sliding surfaces of the seal rings, also contributes to the heat removal.
In prior art designs, the non-rotating seal ring is made of carbon, for example, and the rotating seal ring is usually made of steel with a great hardness of the sliding surface, such as stellite or chrome steel in order to obtain a satisfactory sliding, and a high strength at the same time.
With high speeds and surface pressures, the temperatures of the slide rings may rise to such extremes that the packing liquid, such as oil, decomposes on the slide surface and forms undesirable deposits which increase the leak into the gas space.